The present invention relates to agriculture and agricultural machinery, and more particularly to a novel, improved method and apparatus for transplanting crops in the field. Specifically, the invention disclosed here enables precise, controlled transplanting of seedlings from greenhouse trays. "Seedling" as used herein is used as employed in the field, and refers to the seedling plant as well as the mass of earth that the plant's roots permeate, this earth mass and roots being referred to as a ball or plug.
Transplanting row and vegetable crops has been found to be an effective agricultural process for so-called row crops, such as celery, tomatoes, broccoli, brussel sprouts, cauliflower, lettuce, peppers, beets, asparagus, etc. With respect to high density crops, those in which between 30,000 to 45,000 plants per acre are planted, it has become very advantageous to provide some type of agricultural machine or apparatus for the transplanting process. One type of transplanting method and apparatus is disclosed in Talbott, U.S. Pat. No. 4,182,247. That patent discloses a vehicle which is transportable over a field, and it includes a carriage reciprocally shiftable relative to the length of the vehicle's frame.
Incorporated on the carriage are a plurality of fluid-dispensing nozzles which are operable for injecting fluid jets into the ground to form cavities for receiving seedlings. The vehicle is pulled behind a tractor and the carriage is maintained substantially stationary relative to the ground during the fluid injection step with the vehicle being continuously advanced. After the seedling-receiving cavities are formed, seedlings are manually introduced thereinto. The vehicle includes seats and a support for holding seedling trays so that an individual or individuals may be seated on the vehicle, and during transport over a field, may remove the seedlings manually from a seedling tray and place them into the pre-formed cavities.
An automatic method and apparatus for transplanting crops is disclosed in an invention of Talbott, pending application Ser. No. 493,992 filed on May 12, 1983. In that application, there is disclosed a transplanting apparatus which receives trays of seedlings from a greenhouse and sequentially displaces the seedlings from the trays into selected crop rows via an automatic process. The method and apparatus disclosed in that application also utilized a plurality of fluid dispensers mounted on the transplanting apparatus selectively operable for directing fluid against the ground to form a plurality of laterally spaced-apart plant-receiving cavities.
The fluid dispensers are positioned in advance of a carriage which is provided on the apparatus for receiving a plurality of seedling trays. The carriage is provided with plant setters thereon selectively operable for engaging selected seedlings in selected rows of the seedling trays and displacing them substantially vertically downwardly from a selected cell in the seedling tray into a plant-receiving cavity. The application discloses a carriage which, during operation of the plant setters, moves rearwardly along the apparatus, at a rate equal to the forward travel of the apparatus so that the plant setters may be actuated to dislodge a plant from a cell and urge it vertically downwardly into a plant-receiving cavity.
The above transplanting methods and apparatus have been found to work efficiently, but the use of injecting a fluid into the ground to form a crop-receiving cavity has certain limitations, e.g., when the ground is very hard, compact or of clay-like material, etc. It has been found that a trouble-free method to create crop-receiving cavities, for the transplanting of seedlings, can be most efficiently formed by use of conventional shoes or "openers," which are small plows, for opening up the ground to create a furrow for receiving transplanted seedlings. However, such conventional devices use complicated mechanisms to transfer or deposit seedlings into the furrows created, and a continuing problem resides in the unavailability of a method to pack soil around the transplanted seedling so that it is held firmly in place after the transplanting process. Prior art transplanters, which utilize shoes to create furrows, incorporate complicated devices to hold the seedling while dirt is directed around the seedling by compaction wheels, etc. Methods for keeping the plants upright include arrangements for either holding the seedling by its leaves or by the "root ball" externally.
In machines where the leaves are held, there is no assurance that the root ball will be placed or oriented upright in the furrow. If the seedling is not transplanted upright, it may grow in a deformed manner, and will not mature at a rate consistent with other seedlings in the field, resulting in an uneven harvest.
Machines incorporating retaining devices to hold the root ball externally, such as rods or wires which grip the outside of the plant, or various types of wires which move along with the machine to hold the plant upright, suffer from drawbacks. Specifically, as the soil is compacted around the plant, the devices become jammed with the soil or become impeded so that they are damaged or cannot be retracted. Moreover, if the soil contains lumps or "clods," the wires used to hold the root ball upright prevent the soil from packing around the seedling, and therefore the seedling is not transplanted securely in place.
With the above deficiencies in the prior art in mind, it is a general object of the present invention to provide a method and vehicular apparatus for transplanting seedlings which incorporates the steps of creating a seedling-receiving furrow in the ground, displacing a seedling from a tray mounted on the apparatus and depositing it vertically downwardly into the furrow; thereafter the seedling is held substantially vertically upright by a plant setter mechanism while soil is closed back or packed around the seedling. After complete packing has occurred, the plant setter mechanism is actuated to release its hold on the seedling. The key objective is to maintain the seedling upright, during the soil-packing step, otherwise the soil will knock or kick the plant over.
Another object of the present invention is to provide a plant setter mechanism which is operable for controllably displacing a seedling from a first location, such as from a seedling tray, and depositing it at a second location such as the furrow created by the shoe. To this end, an objective of the present invention is to provide an elongate impaling means or "spear" which is dimensioned for insertion into a seedling, when the seedling is in the tray, and a seedling displacement means defined by an elongate sleeve dimensioned for coaxially and freely receiving the impaling means therethrough which engages the upper surface of the seedling. A link means is provided for transferring motion from a pneumatic device, such as a pneumatically-operated rod and cylinder, to the displacement means only after the impaling means has been extended for penetration into the seedling a predetermined distance. Thus, the impaling means orients the seedling substantially vertically during its downward descent by the displacement means, and holds it in that position during the entire soil-packing sequence. Upon completion of that step, the link means ensures that the impaling means will be precisely ejected or retracted prior to the displacement means being retracted.
Another object of the present invention is to provide a plant setter mechanism, as described above, in which detent means are used for holding the link means substantially stationary, at the beginning of the downstroke of the impaling means and for a predetermined range of travel thereof, prior to relative movement of the displacement means. The use of the detent means on the downstroke ensures that internal penetration or insertion of the impaling means into the seedling occurs prior to engagement on its upper surface by the displacement means, thereby resulting in controlled displacement of the seedling from a seedling tray and subsequent deposition in the ground-created furrow.
Another object of the present invention is to provide a combination shoe and plant setter mechanism as described above which contemplates that the shoe will be fixed to a "float" or skid plate and moved therewith, while the plant setter mechanism is mounted on a carriage, enabling the seedling, contained in a seedling tray, to be held stationary relative to the ground during movement of the transplanting machine so that the plant setter mechanism may displace the seedling into the furrow, after which time the soil may be packed around the seedling by means of closure blades provided on the skid plate at the trailing or downstream end of the opener shoe.
These and additional objects and advantages of the present invention will be more readily understood after a consideration of the drawings and the detailed description of the preferred embodiment.